Today's complex data networks are vital to the operation of many businesses. It is therefore very important that these data networks operate continuously and as reliably as possible. When errors occur, they must be quickly and efficiently identified so that any network problems can be quickly cured. It is preferable that mechanisms for identifying errors in a network are implemented in a scalable manner so that such mechanisms work equally well regardless of the size of the network.
Sometimes errors can occur in a network that cause packets to be misdirected. For example, packets that are meant to traverse the network from a source to a destination may be directed from the source to the wrong destination. It is therefore advantageous to be able to monitor the paths that packets take through the network so that any groups of packets that are being misdirected can be identified, and appropriate action taken. One way to monitor the paths that the packets take through the network is to inject probe messages onto the path. The probe message can contain the identity of the path that the source is using for the packets. The destination can listen for the probe messages and verify that the path identified in the message is correct. When the destination fails to receive probe messages containing the correct path identifier, or receives probe messages containing incorrect identifiers, it can notify the network management system of an error in the network.
In multi-protocol label switched (MPLS) networks, paths created using the label distribution protocol (LDP) are not associated with any particular path identifier, so that current probe messages that rely on path identifiers cannot be used. It would be highly advantageous to provide a probe message that can be used in LDP MPLS networks.